Conduct this procedure according to ND T 99 or ND T 180.
The NDDOT modifies this standard to only allow the use of Method A and D. Method D shall only be used in lieu of Method A when there is more than 5% by weight of material retained on the No. 4 sieve.
Method D shall be used without correction for all soil-aggregates which have all materials passing the 3/4" sieve. Corrections must be made according to
ND T 224 for all materials which have 30% or less retained on the 3/4" sieve. If the specified oversized maximum of 30% is exceeded, other methods of compaction control must be used.
Consult the current edition of AASHTO for procedure in its entirety and equipment specification details.
SCOPE
The moisture-density relationship test is also called the Proctor test. This test method determines the relationship between the moisture content and the density of soils compacted in a mold. Two different standards of moisture- density relationships are presently in use by the NDDOT. They vary mainly in the compaction energy applied to the soil in the mold. The two standards and their features are summarized below.
METHOD A
FEATURE ND T 99 ND T 180
Weight of Compaction Rammer 5.5 lbs 10 lbs
Distance of Drop 12" 18"
Number of Soil Layers 3 5
Diameter of Mold 4" 4"
Soil Passing Sieve Size No. 4 No. 4
2/13/2015 Revised ND T 99 and ND T 180
____________________________________________________________________
ND T 99 and ND T 180 Page 2 of 8
METHOD D
FEATURE ND T 99 ND T 180
Weight of Compaction Rammer 5.5 lbs 10 lbs
Distance of Drop 12" 18"
Number of Soil Layers 3 5
Diameter of Mold 6" 6"
Soil Passing Sieve Size 3/4" 3/4"
Rammer, Blows/Layer 56 56
REFERENCED DOCUMENTS
AASHTO T 99 and T 180 – Moisture Density Relations of Soils
ND T 217 and AASHTO T 217 - Determination of Moisture in Soil by Means of Calcium Carbide Gas Pressure Moisture Tester (Speedy)
ND T 265 and AASHTO T 265 - Laboratory Determination of Moisture Content of Soils
ND D 2167 and ASTM D 2167 - Density and Unit Weight of Soil in Place by the Rubber-Balloon Method
ND D 4643 and ASTM D 4643 - Determination of Moisture Content of Soil by Microwave Oven Heating
APPARATUS
Balance, readable to 0.01 lbs. (5 g) Oven
No. 4 (4.75 mm) sieve Mixing tools
Moisture sample cans with lids Straightedge, 10" long
Knife
Compaction equipment including density mold, base and collar, and compacting rammer and guide
SAMPLE SIZE
Method A - A representative soil sample of approximately 35 lbs (15.9 kg) is required for the Multi-Point Moisture Density Relationship Test, and
approximately 7 lbs (3.2 kg) is required for the One-Point Moisture Density Relationship Test.
____________________________________________________________________
ND T 99 and ND T 180 Page 3 of 8
Method D - A representative soil sample of approximately 125 lbs (55 kg) is required for the Multi-Point Moisture Density Relationship Test, and
approximately 25 lbs (11 kg) is required for the One-Point Moisture Density Relationship Test.
PROCEDURE
Multi-Point Moisture Density Relationship - Mechanical and Manual Record this information on SFN 10063, "Moisture Density Relationship Test." Calculate and record to the accuracy indicated.
If the soil is damp when received, dry until it is easily crumbled under a trowel. It can be air dried or oven dried at a temperature up to 140°F (60°C). Break up the soil chunks so that the entire sample passes through the No. 4 sieve. Avoid reducing the natural size of the particles. Discard any individual particles of material retained on the No. 4 sieve or organic material. Divide the sample into five representative samples of 7 lbs each.
Thoroughly mix the first test sample with water to dampen it approximately four percentage points below optimum moisture. A good indication of a soil being right for the first point is if the soil barely forms a “cast” when squeezed together. Specimen shall be placed in moisture proof container and covered to prevent moisture loss. Mix remaining specimens in the same manner as test sample one, increasing water content by approximately one or two percentage points (not exceeding 2.5%) over each preceding specimen. This can be accomplished by adding approximately 60 mL* of water. Allow soil samples to cure in moisture proof containers for a minimum of 12 hours.
*If using Method D, the water added to the sample must be increased from approximately 60 mL to approximately 215 mL.
Weigh the empty mold without the base plate or collar and record to the nearest 0.01 lb (5 g).
From test sample one: add sufficient material to the mold to produce a
compacted layer of approximately 1-3/4" for ND T 99, or 1" for ND T 180. Gently level the soil surface in the mold. *Using a manual compaction rammer or a similar device with a 2" face (50 mm), lightly tamp the soil until it is no longer loose or fluffy. Compact the soil with **25 evenly distributed blows of the
compaction rammer. After each layer, trim any soil along the mold walls that has not been compacted with a knife and distribute on top of the layer.
*When completing this process using a mechanical compactor, it is recommended to use a spare or extra replacement rammer.
2/13/2015 Revised ND T 99 and ND T 180
____________________________________________________________________
ND T 99 and ND T 180 Page 4 of 8
**If using Method D, compact the soil with **56 evenly distributed blows. When using a manual compactor, remember to hold the rammer perpendicular to the base of the mold and lift the rammer to its maximum upward position.
Repeat this procedure adding more soil from the same sample each time so that at the end of the last cycle, the top surface of the compacted soil is above the top rim of the mold when the collar is removed.
Remove the collar and trim off the extruding soil level with the top of the mold. In removing the collar, rotate it to break the bond between it and the soil before lifting it off the mold. This prevents dislodging chunks of compacted soil when lifting the collar off. The trimming consists of many small scraping motions with a knife or straightedge.
After trimming the soil level with the top of the mold, clean all loose material from the outside of the mold. Weigh the soil and mold to the nearest 0.01 lb (5 g) and record. Subtract the weight of the mold from this weight and divide the result by the volume of the mold. Record results as wet density in pounds per cubic foot (pcf). Compute and record wet density to the nearest 0.1 pcf.
Wet Weight of Soil = Weight of Mold + Soil – Weight of Mold Wet Density, pcf = Wet Weight of Soil/Volume of Mold
Remove the soil from the mold and slice through the center vertically. Obtain a representative sample of approximately 100 g from one of the cut faces. Take the sample from the full length of the inside of the soil cylinder. Place the moist sample in a container, cover and weigh. Record the weight of the wet soil. Record this and all moisture weights to the nearest 0.1 g.
Dry the sample to a constant weight according to ND T 265, Laboratory Determination of Moisture Content of Soils.
Calculate the percent moisture to the nearest 0.1%. Compute and record dry density to the nearest 0.1 pcf.
The formula is as follows:
Dry Density, pcf = (Wet Density X 100)/(100 + % Moisture)
Using specimen number two, repeat the compaction procedure previously described. Continue this process, with the remaining samples, until there is a decrease in the wet density per cubic foot.
____________________________________________________________________
ND T 99 and ND T 180 Page 5 of 8
GRAPH
The objective of this procedure is to determine the maximum dry density and optimum moisture content for this particular soil. Based on the results obtained from conducting consecutive Proctors with changes in moisture, plot each test result on the cross-ruled area on the form with the moisture content plotted on the abscissa (x) and the density on the ordinate (y).
After all the results are plotted, draw a smooth flowing curve through or close to the plotted points. From the peak of the curve, select the maximum dry density and optimum moisture. Report the maximum dry density to the nearest
1-lb./cu.ft. and the optimum moisture to the nearest 0.1%. NOTES
During compaction, the mold shall rest firmly on a dense, uniform, rigid, and stable foundation or base. This base shall remain stationary during the
compaction process. Each of the following has been found to be a satisfactory base on which to rest the mold during compaction of the soil: (1) a block of concrete with a mass not less than 200 lbs (90 kg) supported by a relatively stable foundation; (2) a sound concrete floor; and (3) for field applications such surfaces are found in concrete box culverts, bridges, and pavements.
The moisture-density test is used to establish a value of density on which construction requirements can be based. It is a test conducted on a single identifiable soil and results may vary considerably between different soils. Make every effort to space the moisture contents no further apart than 2.5% in order to accurately determine the maximum dry density and optimum moisture content.
CALIBRATION
A calibration check of the equipment should be performed annually as a minimum, or whenever damage or repair occurs.
One-Point Moisture Density Relationship with Typical Moisture-Density Curve Method
After analyzing a large number of both ND T 99 and ND T 180 moisture-density curves that generally represent statewide soil types, it was found the curves follow the trends shown on the graphs on the following pages. The graphs with the following procedure may be used in place of performing the entire moisture- density relationship test. It is recommended that the Multi-Point Moisture Density Relationship be used whenever possible.
2/13/2015 Revised ND T 99 and ND T 180
____________________________________________________________________
ND T 99 and ND T 180 Page 6 of 8
PROCEDURE
The procedure that follows is written for a test using one sample of approximately 7 lbs (3.2 kg) of material. Thoroughly mix the soil sample with water and dampen it approximately to, but not over, Optimum Moisture. Conduct a Proctor test as previously described in the Multi-Point Moisture Density Relationship.
GRAPH
Use either of the following graphs, ND T 99 or ND T 180, whichever is appropriate, to locate the point defined by the two values obtained from the Proctor.
If the point lies directly on a curve, follow this curve to its peak and read off the maximum dry density and optimum moisture content. If the point lays in-between two curves, follow the two curves to their peaks and interpolate the maximum dry density and optimum moisture content. Report the maximum dry density to the nearest 1-lb./cu.ft. and report the optimum moisture to the nearest 0.1%.
NOTES
When the rubber balloon method is used for the density test, use the same material from the hole for the one-point determination. To get sufficient material, enlarge the hole after the rubber balloon test is complete and use the additional material collected.
In order to perform the test in conjunction with and at the same location as the in- place density test, there are steel-capped, wooden pedestals available to support the mold base plate. During compaction, place the mold and pedestal on firm level ground.
Perform moisture content test according to ND T 217, Determination of Moisture in Soil by Means of Calcium Carbide Gas Pressure Moisture Tester (Speedy). Or, if there is a field lab available to conduct the moisture determination, obtain the sample in the same manner described previously according to ND D 4643, Determination of Moisture Content of Soil by Microwave Oven Heating, and ND T 265, Laboratory Determination of Moisture Content of Soils.
When using the graphs, a soil on the wet side of optimum could result in a substantial error when selecting the maximum dry density. Most specifications require the moisture content to be at or above optimum, thus it can be assumed that this is the condition that most samples are in. If the sample is judged to be slightly wetter than optimum, dry it to a condition slightly drier than optimum before compacting.
114 110 106 102 98 94 90 86 82 78 74 70 4 8 12 16 20 24 28 32 36 38